1. Field of the Invention
This invention relates to the chlorination of copper phthalocyanine to produce a green shade of copper phthalocyanine.
2. Description of the Prior Art
It is well known that the shade of copper phthalocyanine varies according to the number of chlorine atoms present in the molecule. Thus the blue shade of the unchorinated copper phthalocyanine changes to green-blue when 8 chlorine atoms are introduced and to a more intense green shade when 12 or more chlorine atoms are incorporated into the copper phthalocyanine molecule.
In the past, processes for the preparation of phthalocyanine green employed large amounts of expensive reagents as solvents such as chlorosulfonic acid which are then discarded after the reaction is complete. Such processes are expensive due both to the waste of the discarded solvent and to long reaction times required to make the phthalocyanine green.
Chlorinated metal phthalocyanines have been produced by a variety of methods. As halogenating agents, it has been proposed to employ normally liquid halogenating agents such as sulfuryl chloride and thionyl chloride. Such halogen carriers as aluminum chloride are used in limited quantities, but the bulk of the reaction medium consists of the liquid halogenating agent. In other words, the halogenating agent is dependent upon to supply the liquid medium for the reaction.
U.S. Pat. No. 3,320,276 teaches that sulfuryl chloride will halogenate a metal-free phthalocyanine or a metal complex of phthalocyanine such as copper phthalocyanine without the addition of elemental halogen in the presence of aluminum chloride and/or aluminum bromide and, preferably, containing an alkali metal halide such as sodium chloride with sulfur monochloride present as a halogen carrier. However, this process requires the aluminum chloride or aluminum bromide be in the form of a fluid melt. This has many disadvantages since it requires means for heating and maintaining the aluminum chloride in a fluid state. Large quantities of the aluminum chloride are required in this process, for example, all the examples call for 100 parts of anhydrous aluminum chloride for 10 parts of copper phthalocyanine. Further, the hydrolyzed aluminum chloride (at the end of the reaction) is discarded and may contribute to effluent problems.
Moser and Thomas, Phthalocyanine Compounds, pages 172-179, Reinhold Publishing Corporation, New York (1963), discloses the use of copper chloride as a catalyst for chlorinating copper phthalocyanine. However, it does not disclose the use of copper chloride in a process involving the reaction of the copper phthalocyanine with sulfuryl chloride.
______________________________________ Other References of Interest Pat. No. Issued Inventor(s) ______________________________________ 2,214,469 9/10/40 Patrick et al 3,424,759 1/28/69 Stewart et al 4,077,974 3/7/78 Wessling 4,091,028 5/23/78 Barraclough et al 4,035,383 7/12/77 Sweet 2,873,279 2/10/59 Randall et al 2,793,214 5/21/57 Holtzman et al 2,662,085 12/8/53 Holtzman et al 2,862,924 12/2/58 Caliezi et al ______________________________________